Police say a man was repeatedly punched in the face after a brief disagreement in town early yesterday morning (Sunday 8 December).
The man suffered cuts and bruises as a result of the attack, that took place sometime between 02:25 and 02:40 outside Vauxhall Gardens on Vauxhall Street.
Police are looking for the suspect, who was with a group of 5-10 people just before the assault.
He's described as English, in his late 20s to early 30s, with receding brown hair and facial stubble. He was wearing a blue top.
After the attack, he was seen going in the direction of New Street and Val Plaisant.
The victim is white, around 6"0 tall, with short light brown hair. He was dressed in a black tuxedo and carrying a white takeaway bag.
Anyone who saw what happened is asked to call police on 612612, CrimeStoppers anonymously on 0800 555 111 or via their Anonymous Online Form at Crimestoppers-uk.org.